A total of 42 patients from the five participating institutions were randomized into this cooperative study during 1973 with 9 patients entered from M.D. Anderson. In addition 2 patients from M.D. Anderson were entered in January, 1974. Hormonal "shock" therapy employing intramuscular injections of 100 mg. testosterone propionate daily for 3 days followed by a resumption of estrogen (diethylstilbestrol diphosphate 50 mg. tid.) has been employed in the 2 patients allocated for standard therapy with improvement in the clinical status recorded in each instance. Cyclophosphamide, 1000 mg./M2 given intravenously as a single dose every 3 weeks, has been administered to the 5 patients initially allocated to that arm of the study, without significant toxicity. Five patients have been randomized to receive 5-flourouracil, 600 mg./M2 intravenously weekly, with 1 patient developing severe toxicity. There have not been sufficient number of patients on the study long enough, however, to produce more formal references. The research goals for the coming year are to conclude the current evaluation of the investigation of cyclophosphamide and 5-fluorouracil and initiate the second part of the study evaluating the efficacy of Estraycst and Streptozotocin in advanced prostatic carcinoma.